Here's a fun thing about humans: abusers leave a trail of traumatized, angry people. If you are not a witness to their abuse, it's very easy for them to recast those people's actions as abusive and irrational, since neither traumatized people nor angry people are in the best position to be perceived as calm and rational. Because you, yourself, have mainly experienced this person as kind, gentle, and loving, you're willing to accept their explanations for everything.